Denture



Jan; 17, 1939. 5 A 2,144,198

DDDDD RE Patented Jan. 17, 1939 UNITED STATES PATENT OFFiE DENTURE Melvin E. Page, Muskcgon, Mich.

Application April 23, 1936, Serial N0. 75,995

6 Claims.

This invention relates to improvements in dentures.

The main objects of my invention are:

First, to provide a denture characterized by functional efficiency, bilateral balance, incisal and functional balance, and automatic self-adjustability to changing foundations and changed interdenture relationship.

Second, to provide artificial posterior teeth for a denture characterized by} the above named qualities.

Further objects relating to details and economies of my invention will definitely appear from the description to follow. The invention is defined in the claims. 7

Preferedembodiments of my invention are illustrated in the drawing, wherein:

Fig. 1 is a side view of a denture having sets of teeth formed in the manner of or embodying my invention.

Fig. 2 is a plan view of the lower set of teeth of my invention.

Fig, 3 is an enlarged detail sectional view on a line corresponding to line 33 of Fig. 1.

Fig. 4 is an enlarged sectional view through teeth of the upper and lower sets on a line corresponding to line l-4 of Fig. 2.

Fig. 5 is an enlarged sectional view through teeth of the upper and lower sets on a line corresponding to line 5--5 of Fig. 2.

Figs. 6, '7 and 8 are enlarged views illustrating modified embodiments of my invention.

In the making and use of artificial teeth, the mechanical principles involved are quite different 35 from those involved in the functioning of natural teeth. Artificial teeth consist of units of several teeth, one unit for each jaw, and held firmly to the jaw only to the extent to which fit and balance are established and maintained. Continued balance during changed functional relationship of the jaws is most essential to prevent tipping and rocking of the denture. Tipping and rocking'of the dentures produce trauma to the underlying foundations, causing shrinkage or absorption to take place at a much faster rate than normally.

In most cases, some of this shrinkage will occur despite anything the dentist or patient can do to prevent it. Since thelower jaw moves not only toward the upper, but also in a forward direction, if absorption takes place, a changed relationship of the two sets of teeth ensues. Therefore, another desirable feature of artificial teeth should be means of some kind for preserving automatically the original distance between the jaws,

called the vertical distance, while at the same time maintaining function during the changed condition of the foundations.

My invention lies in the provision of artificial posterior teeth that satisfy the mechanical prin ciples involved in the construction and function of artificial teeth, these principles being functional efiiciency, bilateral balance, incisal and functional balance, automatic self-adjustability to changing foundations and changed interdenture relationship, and presence of a proper rest position.

The. teeth of the present invention are used as posterior teeth in artificial dentures. These correspond to the bicuspids and molars of natural teeth. They consist of blocks of porcelain or other suitable material shaped to resemble natural crowns of teeth, except for the occlusal or masticating surfaces. The teeth are fixedly held in a conventional mounting designated by the reference numeral I.

The occlusal surface of each of the lower teeth 2 is shaped or conformed to form two substantially plane surfaces 3, 4 which intersect at an angle of' about 170, the apex being upward with the tooth substance within the angle of the planes. As clearly illustrated in Fig. 3, the buccal plane 4 of the lower teeth is not as wide or of as great area as the lingual plane 3 and. the line of intersection extends substantially from a mesial point to a distro-lingual point.

As illustrated in Fig. l, the line of the intersection has an upward posterior inclination, and the lines of intersection of the planes of the teeth are substantially parallel but not collinear, both when viewed in elevation and in plan.

The occlusal surface of each upper tooth is conformed to form two plane surfaces 5, B inter secting at an angle of approximately 170, the

apex being upward. The tooth substance of the upper teeth is without the intersecting angle. The line of intersection of the surfaces of the upper teeth extends upwardly as shown in Fig. 1, and from an approximately mesial point to a disto-lingual point corresponding to the lines of intersection of the lower teeth. Similar to the lower set, the respective lines of intersection of the plane surfaces of the upper teeth are parallel but non-collinear. The buccal plane 6 in the case of the upper teeth is wider than the lingual plane 5.

I have found that for most effective results the lines of intersection of the lingual and buccal planes of upper and lower posterior teeth should be approximately parallel to a line extending from the center of the chin to a point midway between the two condyles when the sets of teeth are in centric occlusion. This relation will, of course, vary with individual patients and must be adjusted in each case in view of the conformation of the patients jaw structure.

The planes 3, 4, 5, 6 are general in character, the angle of union thereof being only approximate. I have found that an angle of 170 is effective and does not interfere with the gliding of the lower teeth against the upper teeth in the process of mastication. Nearly fiat occlusal surfaces are provided; however, there is enough divergence from the horizontal in the two occlusal planes of each of the teeth to provide bilateral balance between the teeth of the opposing dentures.

The inclination of the lines of intersection up ward and backward is not intended to be fixed, but may vary from a few degrees to many. I have found, however, that a 20-30 inclination is suitable in most cases. The nature of the condylar inclinations and the overjet and overbite of each patient will determine the same.

In accordance with my invention, the incisal teeth I, 8 are likewise ground to form meeting planar surfaces 9, l0, respectively, as illustrated in Fig. 5, whereby the incisal bite is improved. The support, which is given the posterior portions of the denture by the formation of their occlusal surfaces in the manner described, tends to keep the rest position the correct one during changing conditions of the mandible and provide the proper overjet and overbite for the upper anterior teeth.

The planes 3, 4, 5, 6 forming the occlusal surfaces of upper and lower posterior teeth are ground as above stated to form an angle of intersection of approximately 170. 'In this relation, the planes may both be offset from the horizontal. An important feature of my invention resides in the fact that the slope of the buccal plane of the posterior teeth is ground at such an angle to the lingual plane as to conform to the radial movement of the opposing buccal plane with the path of the opposite condyle as a center. By such means, bilateral balance is assured at all times. I have found that an angle of approximately 170 very closely fulfills this requirement. So long as such a relationship exists, the lingual plane may be approximately horizontal or may be at an angle to the horizontal.

Suitable indentations or recesses l l are formed in the surfaces of the teeth to improve the adhesion of food thereto.

The respective buccal and lingual planes are preferably so related that the apexes of the intersecting angles of upper and lower teeth coincide, as illustrated in Fig. 3. Modifications of my invention are possible in this respect and are illustrated in Figs. 6, '7 and 8. In the embodiment of Fig. 6, the angle formed between intersecting planes 3 and 4 is truncated, whereby a space !2 exists between upper and lower posterior teeth; in the embodiment of Fig. '7, it is the angle between planes 5 and 6 which is truncated; and in the embodiment of Fig. 8,.the angle of both teeth is'truncated, whereby a common connecting plane l3 lies between the buccal and lingual planes. Considerable flexibility in this respect is available to the dentist, my improved denture being characterized chiefly from an inventive standpoint in the following respects: 1) the provision of nearly flat occlusal surfaces for the lower posterior teeth with, however, enough divergence from the horizontal of the buccal portion of each tooth to provide bilateral balance with the teeth of the opposing denture, the divergence preferably being brought about by the formation of an obtuse angle ground in the occlusal surfaces; (2) the inclination upwardly and distally of the lines formed by the union of the two planes forming the angle of occlusal surfaces; and (3) the approximate paralleling of the line of intersection of the buccal and lingual plane of each tooth with that of the others, rather than having them follow approximately the curve of the underlying ridges.

Functionally, dentures produced in accordance with my invention have numerous improved characteristics which may be summarized as follows. Bilateral balance is afforded, which, together with the improvement in the incisal bite, by the support afforded by the posterior portions of the denture, produces non-rocking qualities or sta bility of the dentures. Changed anterior posterior relationship of the two jaws is provided for and in the changed anterior-posterior relationship of the jaws, due to the absorption of the bony foundations, the vertical distance between the two jaws is for all practical purposes maintained.

Dentures made with the teeth as described lessen absorption of the underlying ridges since traumatic stresses are minimized, the relationship of the upper with the lower teeth changing with no sacrifice of comfort, utility or esthetics. The lower jaw has a rest position in relation to the upper jaw, a factor which is absent in all oneplane posterior teeth. The overjet and overbite of the upper anteriors can be made to duplicate those of natural teeth, an advantage not obtainable with the use of any other known anatomical posterior teeth so far as I am aware.

t will be obvious that the nearly flat occlusal surfaces of the'lower teeth provide a good food table. The teeth are adaptable to individual requirements by the simple expedient of inclining them either. forward or backward to increase or decrease the angles which the occlusal surfaces present to the horizontal and thereby harmonize with the condylar inclinations and the incisal plane of the individual, and the forces exerted by the lower teeth against the upper teeth tend to keep the mandible in a rest position. which is the retruded and correct position because of the upward distal incline of the teeth.

I have illustrated and described my improve ments in embodiments which I have found very practical. I have not attempted to illustrate or describe other embodiments or adaptations which I contemplate, as it is believed this disclosurewill enable those skilled in the art to embody or adapt my improvements as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a denture, a lower set of posterior teeth having their occlusal surfaces composed of two planes converging obtusely and a third plane between said planes, and an upper set of posterior teeth having their occlusal surfaces in the form of two planes converging obtusely, the lines of intersection of said planes of said upper and lower teeth extending from a forward and downward point to a backward and upward point in a direction approximately parallel to a line extending in a direction from front to rear of the teeth and located laterally midway between the posterior teeth of each set when the sets of teeth are in centric occlusion, said denture permitting relatively free sliding movements both forward and backward and from side to side within the functional range of the jaw movements, the line of intersection of the planes of each tooth being noncolinear with the line of intersection of planes of adjacent teeth of the same set.

2. In a denture, a lower'set of posterior teeth having their occlusal surfaces composed of two planes converging obtusely, and an upper set of posterior teeth having their occlusal surfaces in the form of two planes converging obtusely and a third plane between said last named two planes, the lines of intersection of said planes of said upper and lower teeth extending from a forward and downward point to a backward and upward point in a direction approximately parallel to a line extending in a direction from front to rear of the teeth and located laterally midway between the posterior teeth of each set when the sets of teeth are in centric occlusion, said denture permitting relatively free sliding movements both forward and backward and from side to side within the functional range of the jaw movements, the line of intersection of the planes of each tooth being non-colinear with the line of intersection of planes of adjacent teeth of the same set.

3. In a denture, a lower set of posterior teeth having their occlusal surfaces composed of two planes converging obtusely, and an upper set of posterior teeth having their occlusal surfaces in the form of two planes converging obtusely, the obtusely converging planes of both upper and lower teeth being separated by a plane, the lines of intersection of said planes of said upper and lower teeth extending from a forward and downward point to a backward and upward point in a direction approximately parallel to a line extending in a direction from front to rear of the teeth and located laterally midway between the posterior teeth of each set when the sets of teeth" and backward and from side to side within the functional range of the jaw movements, the line of intersection of the planes of each tooth being non-co linear with the line of intersection of planes of adjacent teeth of the same set.

4. In a denture, the combination of upper and lower sets of posterior teeth having the respective occlusal surfaces thereof in the form of planes intersecting at an obtuse angle of approximately 1'70", the lines of intersection of said planes being substantially parallel, non-colinear and extending entirely across the occlusal surfaces of the teeth in a direction substantially from a lower mesial to an upper disto-lingual point.

5. In artificial teeth, upper and lower sets of posterior teeth meshing on forwardly and laterally inclined surfaces which extend entirely across the occlusal surfaces of the teeth in a front to rear direction, each of said teeth having at least two such inclined surfaces, said inclined surfaces on each tooth being parallel to corresponding surfaces of other teeth in the same set and intersecting at an obtuse angle to provide a line element at the intersection extending entirely across the occlusal surface, said element being parallel to a vertical plane drawn midway between the rearmost posterior teeth and normal to a line between said rearmost teeth, said elements being parallel to and non-colinear with one another in plan and elevation. v

6. In artificial teeth, upper and lower sets of posterior teeth meshing on inclined occlusal surfaces of the teeth, each of said teeth having at least two inclined surfaces intersecting at an obtuse angle to provide a line element common to the intersecting surfaces extending entirely across the occlusal surface, said element being parallel to a vertical plane drawn midway between .the rearmost posterior teeth and normal to a line between said rearmost teeth, said elements being parallel to and non-colinear with one another.

MELVIN E. PAGE. 

